Electric coolant pump having an integrated valve, and method for controlling said valve

ABSTRACT

The present invention advantageously proposes an electrical coolant pump ( 1 ), in particular for the coolant circuit of internal combustion engines for automotive vehicles, comprising a coolant pump motor for driving an impeller ( 6 ) through the intermediary of a pump shaft ( 10 ), and a valve ( 36 ) that is integrated into the pump inlet, wherein for the first time the coolant pump motor constitutes the switching element for the valve ( 36 ). Moreover the present invention for the first time specifies a method for controlling the valve ( 36 ), wherein the work necessary for switching is afforded by the coolant pump motor and is transmitted to the valve ( 36 ), in particular a 3/2-port directional control valve, via the shaft ( 10 ) of the pump motor.

The present invention relates to an electrical coolant pump, inparticular for the coolant circuit of internal combustion engines forautomotive vehicles, and a method for controlling a valve of anelectrical coolant pump.

Various embodiments of pumps for cooling or heating circuits inautomotive vehicles are known to be in practical use.

Thus for example in EP 0 712 744 A1, a circulating pump suited forconveying the coolant is generally discussed in connection with thevehicle heating system that is described there and includes a PCM (i.e.,phase-change device). Moreover in DE 198 03 884 A1 a liquid-cooledinternal combustion engine having a cooling circuit that includes acoolant pump suited therefor is described.

Electrically powered coolant pumps are increasingly utilized as driveelements for cooling circuits of internal combustion engines forautomotive vehicles. In comparison with a pump of a conventional designthat is coupled with the engine speed, these have the advantage of beingindependent of the engine speed and thus also being capable, e.g., ofdelivering coolant at a standstill. A particularly performing and at thesame time extremely compact as well as lightweight design of anelectrical coolant pump has been developed by the applicant of theinstant application. It is discussed in patent application DE 100 47387.3 which is as yet unpublished.

Furthermore an electrically operated coolant pump for a cooling orheating circuit in an automotive vehicle has been disclosed, forexample, in DE 199 21 421 A1. In the case of this coolant pump, thevalve and its housing are jointly arranged on the housing of the pump soas to further reduce the structural space. Here it is a drawback,however, that the valve of DE 199 21 421 A1 is switched via a separatedrive mechanism here having the form of an adjusting motor, and inaddition requires a control unit of its own. It moreover is a drawbackin this design that the coolant is in parts deviated by more than 90° onits way from the inlet via the valve to the coolant pump, resulting inextremely high flow losses. Finally, in this design the valve has to beswitched by the separate drive mechanism while subjected to flow loads,so that high switching or actuating forces disadvantageously becomenecessary.

In view thereof, and in order to avoid the above discussed drawbacks, itis an object of the present invention to propose an electrical coolantpump having a valve that is integrated into the pump inlet, inparticular a combination of pump and valve combined in a common housing,which is of a design as compact as possible, has a low weight, and issimplified in terms of control technology. It is another object of thepresent invention to propose a simplified method for controlling thevalve.

In accordance with the invention, there is proposed for the first timean electrical coolant pump, in particular for the coolant circuit ofinternal combustion engines for automotive vehicles, comprising acoolant pump motor for driving an impeller through the intermediary of apump shaft, and a valve that is integrated into the pump inlet, whereinfor the first time the coolant pump motor constitutes the switchingelement for the valve.

In other words: The work necessary for switching is afforded by thecoolant pump motor and is transmitted to the valve by the shaft of thecoolant pump motor. Thus it is for the first time advantageouslypossible to switch the valve through the intermediary of the coolantpump motor, permitting both a substantial reduction of the number ofcomponents to be installed and a decisive economy of space, as well as asurprising simplification in terms of control technology. At the sametime a decisive weight reduction is achieved. At the same time, thisnovel combination of coolant pump and valve moreover provides thepossibility of utilizing the electronic control system of the pump forcontrolling the valve, so that a separate control for the valves mayalso be done away with.

Here it is advantageously possible through the use of electrical coolantpumps in so-called thermomanagement systems, to do away with thehitherto employed conventional thermostatic valve and replace it withelectrically operated valves, for which purpose the present inventionfor the first time provides the electromotor of the pump as a switchingelement. The valve actuated in this manner allows for higher controldynamics at reduced flow-through pressure losses.

On the one hand, various practical solutions for separate electricaldriving of the valve have been proposed, where in general a rotary valveor an annular slide valve is driven through the intermediary of anelectromotor supported by a transmission. These valve elements withseparate electrical actuation do, however, constitute a considerablecost factor in the framework of the cooling system and are sophisticatedin terms of control technology. In addition to a dedicated actuator anda connecting line to the electrical coolant pump for data equalization,they require a power supply of their own, a control unit of their own,and connection to a data bus system.

In comparison, the inventive combination of coolant pump with integratedvalve provides the most compact design possible. Here the drive motor ofthe pump is for the first time assigned an additional function, namely,the function of “valve actuation.” The constructional requirements forhousing components, electronics, drive mechanism, etc. are reduced to asmallest possible minimum thanks to the twofold function of the coolantpump motor, namely, both a) as a pump drive and b) for valve actuation.

Thus the valve may advantageously have the form of a 3/2-portdirectional valve. In this way the most compact design possible isachieved, with the two inlets of the valve being occupied by therespective coolant flows from the bypass and from the radiator, and theonly outlet of the valve being routed directly away through the pumphousing while flowing around impeller and pump motor. A more compactdesign can hardly be realized with the technical possibilities availablenowadays.

In the inventive combination of coolant pump with integrated valve, thevalve having the form of a 3/2-port directional valve replaces the knownconventional thermostatic valve. It has the two switching positions ofa) “radiator open” or b) “bypass open.” It essentially improves thedynamic control behavior and substantially reduces the pressure loss incomparison with thermostatic valves. Through the particularly compactdesign of this combination, the direct spatial association of the3/2-port directional control valve with the electrical pump furnishesconsiderable advantages of installation when arranged in the coolingsystem of an automotive vehicle. In the inventive combination, theelectromotor of the pump for the first time drives the impeller in theone direction of rotation while actuating the valve, preferably via thepump shaft and a free-wheel, in the other one.

In a preferred embodiment, the valve includes a flat disc, preferably arotary valve element, as a valve member. Such a valve disc or rotaryvalve element offer the advantage of a place-saving design combined withhigh functional safety. Moreover a valve disc or a rotary valve elementmay be mounted and sealed with particularly ease.

In accordance with a further preferred embodiment, the rotary valveelement has two positions preferably having the form of lock-inpositions. The two switching positions are a) “radiator open” and b)“bypass open.” The rotary valve element may, for example, snap into acorresponding recess in the housing encompassing the rotary valveelement by means of an integrally formed, springy nose, so that themaintenance of pre-defined switching positions is advantageously ensuredin a simple constructive manner.

In accordance with a further preferred embodiment, the rotary valveelement is connected with the pump shaft via a free-wheel. Thefree-wheel prevents transmission of energy to the rotary valve elementwhile the coolant pump motor rotates in the forward running direction.The rotary valve element may thus remain in its current switchingposition while the pump shaft rotates together with the impeller inaccordance with the demanded rotational speed. Moreover this free-wheelpermits transmission of energy to the rotary valve element in thereverse rotational direction of the coolant pump motor only. Therotational movement of the coolant pump motor, which in accordance withthe invention serves as a switching element for the valve, is thusadvantageously made use of for providing the switching movement. Atransmission or other reversing mechanisms for power transmission mayaccordingly be omitted, which in turn results in an advantageousreduction of the number of components.

In a further preferred embodiment of the inventive combination ofelectrical coolant pump and integrated valve, the valve may be switched,in particular cyclically, by rotation of the rotary valve elementthrough respective angular sections of 180 degrees in the reverserotational direction of the coolant pump motor. As a result, not only isthe rotary movement available from the pump motor advantageouslyutilized for switching the valve, but at the same time a clearseparation of the twofold function of a) pump drive and b) valveactuation is ensured in that the reverse rotational direction isprovided for switching the valve, and the forward running direction isprovided for conveying the coolant. Thus it is permanently ensured thatswitching the valve will only take place in the load-free condition.This furnishes the additional advantage of no additional pressure orflow forces acting on the rotary valve performing the function of valvemember in the valve. Switching of the rotary valve thus becomessubstantially easier. As a result, the valve may advantageously beactuated even by surprisingly low switching forces. The sophisticatedseparate switching drive mechanisms for the valve known from practicaluse may thus be suppressed entirely. Moreover no additional auxiliarydevices are necessary for discerning the two switching positions of a)“radiator open” or b) “bypass open”, for the rotary valve iscontinuously rotated on in respective cycles of half turns and thereforenevertheless switches back and forth in a cyclically alternating mannerbetween these two switching positions although the direction ofrotation, or movement, remains the same. Confusion or erroneousinterpretation of the respective switching position is thus excluded.Advantageously it is possible to achieve additional switching safety ifthe switching position assumed last is stored in a buffer memory fordata management.

In accordance with a further preferred embodiment, the rotary valveelement includes flow guide means. Hereby it is advantageously possibleto adjust an optimized direction of flow—arriving in accordance with theswitching position from the bypass or from the radiator—toward thecenter or longitudinal axis of the coolant pump, so that an optimal flowaround the impeller is ensured, and thus a maximum possible throughputis obtained at the lowest possible pressure losses.

In a further preferred embodiment, the 3/2-port directional controlvalve has in its housing portion another inlet from the heating returnwhich preferably is permanently open. The heating return here ispreferably arranged in the housing portion facing away from the pumpmotor, in the gusset range between the inlet of the bypass and the inletof the radiator, preferably in a plane through which the longitudinalaxis of the pump extends. Hereby it is advantageously ensured thatindependently of the operating condition of the internal combustionengine of the automotive vehicle, heat may be supplied to the heatingcircuit for air-conditioning the passenger cabin in the vehicle as earlyas from the startup process.

In accordance with a further preferred embodiment, the coolant pumpcontrol unit is at the same time provided for controlling the valve.This in turn helps save both components and electronic controlcomponentry. In addition a further reduction of the construction spaceis hereby achieved. At the same time, it is possible to reduce theweight. Cost savings may moreover be realized.

In a further preferred embodiment, the direction of flow of the coolantarriving from the radiator encloses with the coolant pump longitudinalaxis an angle of less than 40°, preferably less than 30°. Likewise, thedirection of flow of the coolant arriving from the bypass encloses withthe coolant pump longitudinal axis an angle of less than 40°, preferablyless than 30°. In this way it is advantageously ensured thatmaterializing flow losses are as low as possible. For reasons of fluidtechnics, as well, the angle between the bypass flange or radiatorflange and the pump longitudinal axis should be kept small in order toavoid turbulences, which hereby is advantageously achieved.

In accordance with a further preferred embodiment, the inlet of thebypass of the valve includes an additional valve which is biased, inparticular spring-biased. Hereby it is advantageously ensured that forexample in the case of a startup process with a correspondingly coldengine, coolant will not yet be circulated through the engine. At thesame time, the coolant pump may nevertheless already be operated in thisphase, for example in order to initially convey coolant only via theheating circuit, so that the passenger cabin may be heated tocomfortable temperatures as rapidly as possible. If in the meantime theoperating temperature of the engine has risen to such an extent as tonecessitate a first cooling of the engine block, the speed of the pumpmotor may be raised high enough for the flow rate thus obtained togenerate a differential pressure which opens the biased valve in thebypass inlet, so that coolant may be supplied to the engine block viathe bypass circuit. If during subsequent operation of the internalcombustion engine an even higher cooling performance is demanded, thevalve may then be switched over from the switching position “bypassopen” to the switching position “radiator open”, and a correspondinglyhigher cooling performance may be provided by way of the radiator.Hereby it is ensured that the engine block will be cooled, or its heatdissipated, neither too late nor too early, not to mention withoutnecessity. Hereby it is ensured that the lubricant or oil of the enginecan permanently be kept at an optimal operating temperature, without theoccurrence of undesirable heat build-ups or heat losses.

Here for the first time a method is proposed for controlling a valve ofan electrical coolant pump, in particular for the coolant circuit ofinternal combustion engines for automotive vehicles, comprising acoolant pump motor for driving an impeller through the intermediary of apump shaft, and a valve that is integrated into the pump inlet, whereinthe work necessary for switching is afforded by the coolant pump motorand is transmitted to the valve, in particular a 3/2-port directionalcontrol valve, via the shaft of the pump motor. The advantages therebyachieved were already discussed above.

In a further preferred embodiment of the method of the invention, the3/2-port directional control valve includes a rotary valve elementhaving two positions, in particular lock-in positions, namely, switchingpositions a) “radiator open” or b) “bypass open”, and is connected withthe pump shaft via a free-wheel, wherein transmission of energy to therotary valve element through the intermediary of the free-wheel during arotation of the coolant pump motor in a forward direction is excluded,and transmission of energy takes place in a reverse rotational directionof the coolant pump motor only. The advantages connected herewith wereequally already discussed above.

In accordance with a further preferred embodiment of the method, the3/2-port directional control valve is switched over by rotation, inparticular cyclical rotation, of the rotary valve element through arespective angular section of 180 degrees in the reverse rotationdirection of the coolant pump motor.

For switching over the 3/2-port directional control valve, in a furtherpreferred embodiment of the inventive method the coolant pump motorrunning in a forward direction is briefly stopped to then be driven in areverse rotational direction, again stopped briefly, and finally againoperated in the forward running direction. Hereby it is made sure that aclear separation between coolant delivery and switching of the valveposition exists. Moreover the valve is switched over in the load-freecondition only and accordingly may be actuated even by low switchingforces. Furthermore in this way unambiguous switching positions areobtainable in a relatively simple manner.

In a further preferred embodiment of the method, running of the rotormay be monitored, e.g., with the aid of a Hall-effect sensor. Rotorposition, rotor angular position, as well as current development mayhere be monitored with the aid of the already existing electronic unitof the brushless pump motor in order to determine when the rotary valveelement has left a particular switching position, in particular lock-inposition, and assumed the other one. Feedback of the position of therotary valve element via the mechanical coupling thereof by means of thefree-wheel via the drive shaft to the rotor is here advantageously madeuse of. For, depending on the switching position and angular position ofthe rotary valve element, relative facility of rotation of the rotaryvalve element in the course of switching over, or in turn relativestiffness of rotation upon snapping in or out can be detected. Thisbrings about different voltage/current developments in the stator coilswhich may be measured and evaluated correspondingly. Thus it isadvantageously possible with minimum expense to obtain a determinationof the respective position of the rotary valve element with maximumpossible accuracy.

In a further preferred embodiment, a coolant volume flow demanded for aparticular coolant circulation or coolant throughput is adjusted withthe aid of the pump speed of the coolant pump. This provides theadvantage of particularly fine regulation of cooling of the vehicleengine in combination with an improved dynamic control behavior withoutpressure losses in the cooling circuit.

The above described invention shall in the following be explained inmore detail by way of exemplary embodiments while making reference tothe figures of the drawing, wherein:

FIG. 1 is a partly cut-open view of an inventive combination of coolantpump and valve;

FIG. 2 is a front view of the combination of pump and valve representedfrom the side in FIG. 1;

FIG. 3 is an internal view of the valve along the line of section B—Bindicated in FIG. 1; and

FIG. 4 is a three-dimensional view of the inventive combination of pumpand valve shown in FIG. 1 to FIG. 3.

FIG. 1 shows in a partly cut-open view the inventive combination of anelectrical coolant pump with a valve that is integrated into the commonhousing. The coolant pump 1 includes a drain flange 2 located on the topright in this representation for connecting the conduit (notrepresented) leading to the internal combustion engine of the automotivevehicle. The housing 4 for the electronic control system of the pump 1,which projects to the outside, is indicated by its external contour.

In the housing range represented in cut-open fashion in the left half ofthe representation of FIG. 1, the impeller 6 is visible inside thecentral housing portion 8. The impeller 6 is located on a pump shaft 10oriented concentrically with respect to the longitudinal axis X pump ofthe pump. It is driven through the intermediary of a pump motor (notshown). On the right boundary of the range represented in cut-openfashion, a bearing arrangement 12 for mounting the pump shaft 10 isshown. The pump shaft 10 engages a free-wheel 14 with its one end facingaway from the pump motor. The free-wheel 14, in turn, is engaged with avalve member having in this preferred embodiment the form of a rotaryvalve element 16.

The rotary valve element 16 includes flow guide means 18 beingrepresented as having an arcuate section in this FIG. 1 and serving foroptimal guidance of the coolant liquid to the impeller 6.

The free-wheel 14 with the pump shaft 10 engaging therein is, in turn,mounted in the valve housing portion 20.

The free-wheel 14 with the pump shaft 10 engaging therein is arranged ina recess of the rotary valve element 16 having the form of a centralbore 22, for instance. Mounting of the rotary valve element 16 e.g.having the form of a rotary disc valve is achieved with the aid ofcorrespondingly configured portions or marginal sections 23 at theperiphery of the rotary valve element 16. In this way a largely coaxialcentered position of the free-wheel 14 relative to the pump shaft 10 isensured, whereby an inadmissible application of radial forces onto thefree-wheel elements of the free-wheel 14 is excluded.

A first inlet flange 24 serving for connection of the conduit arrivingfrom the bypass (not shown) and a second inlet flange 26 serving forconnection of the supply conduit from the radiator merge into the valvehousing 20 to thus form between each other a centrally arranged gusset27. The inlet from the bypass is symbolized by arrow ZB. The inlet fromthe radiator is symbolized by arrow ZK. Moreover in parallel with thelongitudinal axis X in the range of the gusset 27, the inlet of theheating return is symbolized by arrow ZH.

The valve housing portion 20 is sealed against the pump housing section28 accommodating it with the aid of a seal 30. The pump housing section28, which tapers in a direction toward the center of the pump, opensinto the central housing portion 8 of the coolant pump 1.

In the connection flange 24 of the bypass inlet ZB another valve 32 isshown which is biased with the aid of a spring 34 and serves for closingthe bypass inlet up to a particular differential pressure. Once thisdifferential pressure is exceeded due to a particular coolant throughputof the pump 1, the valve 32 opens to allow the flow of coolant via thebypass circuit from the bypass of the internal combustion engine of theautomotive vehicle through the valve 36 into the pump center of the pump1, under the condition that the valve is in the “bypass open” position.

In FIG. 2 the inventive combination of pump 1 and valve 36 asrepresented in FIG. 1 is shown in a lateral view, wherein with regard toFIG. 1 a viewing direction from the left along the longitudinal axis Xwas selected. In the inlet flange 24 represented to be upwardly open,the particular construction of the additional valve 32, which is biasedby a spring not shown in this representation, is illustrated. The valve32 includes flow passages 38 arranged in the manner of ring segments.Moreover the downwardly directed, continuously open inlet flange 26 forthe inlet from the radiator is shown. To the left thereof, on a levelwith the center plane extending through the longitudinal axis X, the endof the inlet flange 40 for the heating return is shown which faces theviewer. On the right, externally on the housing of the pump 1, thehousing cover 4 of the electronic control system is represented. Thiselectronic control system is used jointly for controlling both the pumpand the valve. Separate control of the valve is not necessary in theinventive combination of pump and valve. Upwardly to the rear, themargin of the connection flange 2 for the outlet toward the vehicleengine is still partly visible.

In FIG. 3, a view from inside corresponding to the line of sectionindicated by arrows B—B when viewing from the right in the directionparallel to the pump longitudinal axis is shown. The cut-open housing 20of the valve is discernible. The pump longitudinal axis X extendsperpendicular to the plane of drawing. In the center of the verticalaxis Y and of the lateral axis Z, the end of the pump shaft 10 facingaway from the pump motor is shown in sectional view. It is engaged withthe free-wheel 14.

In the representation in accordance with FIG. 3 approximately at thebottom left, a nose-type protrusion 42 of the rotary valve element 16 isshown, with this nose-type protrusion 42 locking into a correspondingrecess 44′ or 44″, respectively, in the housing 20. The nose 42 lockinginto the recess 44′ here represents a valve switching position “bypassopen”, and the nose 42 locking into the opposite recess 44″ spaced apartby 180 degrees represents a switching position “radiator open.” In orderto allow spring-biased snapping of the nose 42 of the rotary valveelement 16 into recesses 44′ and 44″, respectively, similar to aspring-supported latch member, the nose 42 is supported by an arm 46contained in the contour of the rotary valve element 16, with a slot 48remaining between the arm 46 and the remaining contour of the rotaryvalve element 16.

Moreover in FIG. 3 an opening 50′ or 50″, respectively, is shown whichensures the inlet from the heating return to permanently remain open ineach switching position of the valve 36. The opening 52, which independence on the switching position clears either the inlet from thebypass or the inlet from the radiator, is optimized in terms of fluidtechnics in the variant represented here, and in terms of its contour isreminiscent of a hybrid form of reniform and curved triangle. Theexternal ends of the connection flanges for both the inlet of the bypass24 and the inlet from the radiator 26 are also indicated.

In FIG. 4, the exemplary embodiment of an inventive combination of pump1 and valve 36 as shown in various views in FIGS. 1 to 3 is shown in athree-dimensional view obliquely from the front. The housing of the pump1 is closed completely in this representation. Behind the housingportion 4 the common electronic control system for the pump and thevalve is concealed. In the covered rear housing portion 54 of the pump 1the pump motor is concealed, whereas in the forward necking in thecentral portion 8 the impeller 10 (not shown) is concealed. In frontthereof in this representation in accordance with FIG. 4 there is thevalve housing portion 20. Facing the viewer to the left there are inletflanges 24 for the inlet from the bypass and 26 for the inlet from theradiator and also 40 for the inlet from the heating return.

The present invention thus for the first time advantageously creates anelectrical coolant pump, in particular for the coolant circuit ofinternal combustion engines for automotive vehicles, comprising acoolant pump motor for driving an impeller through the intermediary of apump shaft, and a valve that is integrated into the pump inlet, whereinfor the first time the coolant pump motor constitutes the switchingelement for the valve. Moreover the present invention for the first timespecifies a method for controlling the valve, wherein the work necessaryfor switching is afforded by the coolant pump motor and is transmittedto the valve, in particular a 3/2-port directional control valve, viathe shaft of the pump motor.

Moreover in an exemplary variant of the inventive combination of acoolant pump integrated into a housing with a valve, the valve isarranged in the inlet of the electrical axial-flow pump. The valve hasthe form of a rotary disc valve. Two axial inlets form the connectionsfor radiator return and engine bypass. The rotary disc valve ispositioned in the two switching positions a) “radiator open” and b)“bypass open” by two lock-in positions spaced apart by 180 degrees. Theswitching process is performed by the electronic unit of the pump motorwhich recognizes the changes in the development of the current whichrises so as to overcome a lock-in position. It moreover evaluates therotary angle signal supplied, e.g., by a Hall-effect sensor of thebrushless pump motor. Position recognition may, e.g., also be performedby a current observer, inasmuch as different differential pressuresmanifest for a) “radiator open” or b) “bypass open” and thus differentcurrent values may be observed for a particular reference speed,depending on the switching position. The position value recognized lastis stored in a memory. Furthermore the rotary disc valve is rotatablymounted in the circumference of the valve housing portion. The pumpmotor shaft is prolonged toward the front to establish engagement in afree-wheel. Here the free-wheel in turn is arranged in an internal boreof the rotary valve and drivingly engages the latter in the reverserunning direction of the pump motor. In pumping operation, thefree-wheel is opened. The shaft rotates while largely free fromadditional friction. For actuating the valve, the motor is brieflystopped and reversed. Owing to the thermal time constant, this does nothave any negative effects in terms of an inadmissible temperature riseof pump motor and/or internal combustion engine. This makes use of thed. c. motor's property of being able to temporarily exert a very highstarting torque which is higher than the continuous operation torque bya factor 10.

The inventive combination of a pump with an integrated valve includingintegrated electronic control componentry is a mechatronic system whichconstitutes the central unit of a thermomanagement system for futurecooling systems. The highly integrated structure together with theassignment of double functions to components results in an extremelycompact system exhibiting clear advantages in comparison with knownsolutions; this also becomes manifest through reduced overall costs.

1. An electrical coolant pump (1), in particular for the coolant circuitof internal combustion engines for automotive vehicles, comprising acoolant pump motor for driving an impeller (6) through the intermediaryof a pump shaft (10), and a valve (36) that is integrated into the pumpinlet, characterized in that said coolant pump motor constitutes theswitching element for said valve (36), and in that said valve (36) is a3/2-port directional control valve.
 2. The electrical coolant pump (1)in accordance with claim 1, characterized in that said valve (36)includes a flat disc, preferably a rotary valve element (16), as a valvemember.
 3. The electrical coolant pump (1) in accordance with claim 2,characterized in that said rotary valve element (16) has two positions,in particular lock-in positions, namely, the switching positions a)“radiator open” or b) “bypass open.”
 4. The electrical coolant pump (1)in accordance with claim 2, characterized in that said rotary valveelement (16) is connected to said pump shaft (10) via a free-wheel (14),wherein during a rotation of said coolant pump motor in the forwardrunning direction, said free-wheel (14) excludes transmission of energyto said rotary valve element (16) while permitting transmission ofenergy in the reverse rotation direction of said coolant pump motoronly.
 5. The electrical coolant pump (1) in accordance with claim 2,characterized in that said valve (36) may be switched by rotation, inparticular cyclical rotation, of said rotary valve element (16) througha respective angular section of 180 degrees in the reverse rotationaldirection of said coolant pump motor.
 6. The electrical coolant pump (1)in accordance with claim 2, characterized in that said rotary valveelement (16) includes flow guide means (18).
 7. The electrical coolantpump (1) in accordance with claim 1, characterized in that said 3/2-portdirectional control valve comprises in its housing portion (20) anotherinlet (ZH; 40) from the heating return, which inlet in particular ispermanently open.
 8. The electrical coolant pump (1) in accordance withclaim 1, characterized in that said coolant pump control unit is at thesame time provided for controlling said 3/2-port directional controlvalve.
 9. The electrical coolant pump (1) in accordance with claim 3,characterized in that the direction of flow of coolant (ZK) arrivingfrom said radiator encloses with said coolant pump longitudinal axis (X)an angle of less than 40°, preferably less than 30°.
 10. The electricalcoolant pump (1) in accordance with claim 3, characterized in that thedirection of flow of coolant (ZB) arriving from said bypass encloseswith said coolant pump longitudinal axis (X) an angle of less than 40°,preferably less than 30°.
 11. The electrical coolant pump (1) inaccordance with any one of claim 3, characterized in hat the inlet ofsaid bypass (24) of said 3/2-port directional control valve includes anadditional valve (32) which is biased, preferably spring biased.
 12. Theelectrical coolant pump (1) in accordance with claim 1, characterized inthat said rotary valve element (16) has two positions, in particularlock-in positions, namely, the switching positions a) “radiator open” orb) “bypass open.”
 13. A method for controlling a valve (36) of anelectrical coolant pump (1), in particular for the coolant circuit ofinternal combustion engines for automotive vehicles, comprising acoolant pump motor for driving an impeller (6) through the intermediaryof a pump shaft (10), and a valve (36) that is integrated into the pumpinlet, and constitutes a switching element for said valve (36)characterized in that the work necessary for switching is afforded bysaid coolant pump motor and is transmitted to said valve (36), inparticular a 3/2-port directional control valve, via said shaft (10) ofsaid pump motor.
 14. The method in accordance with claim 13characterized in that said 3/2-port directional control valve comprisesa rotary valve element (16) having two positions, in particular lock-inpositions, namely, the switching positions a) “radiator open” or b)“bypass open”, and is connected with said pump shaft (10) via afree-wheel (14), wherein transmission of energy to said rotary valveelement (16) through the intermediary of said free-wheel (14) isexcluded during a rotation of said coolant pump motor in a forwardrunning direction, and transmission of energy takes place in a reverserotational direction of said coolant pump motor only.
 15. The method inaccordance with claim 13, characterized in that said 3/2-portdirectional control valve (36) is switched over by rotation, inparticular cyclical rotation, of said rotary valve element (16) througha respective angular section of 180° in the reverse rotation directionof said coolant pump motor.
 16. The method in accordance with any one ofclaims 15, characterized in that for switching over said 3/2-portdirectional control valve (36), said coolant pump motor running in aforward running direction is briefly stopped to then be driven in areverse rotation direction, again stopped briefly, and finally againoperated in the forward running direction.
 17. The method in accordancewith any one of claim 14, characterized in that rotor position, rotorangular position, and current development are monitored with the aid ofthe existing electronic unit of said brushless pump motor, whereby it isdetermined when said rotary valve element (16) has left a particularswitching position, in particular lock-in position, and assumed theother switching position.
 18. The method in accordance with claim 13characterized in that a coolant volume flow demanded for a particularcoolant circulation is adjusted with the aid of the pump speed of saidcoolant pump.